Adapter for fixing spectacle lenses

ABSTRACT

The invention relates to an adapter ( 20 ) for reversibly fixing a spectacle lens ( 10 ) to the shield ( 30 ) of a pair of safety glasses ( 40 ). According to the invention, said adapter ( 20 ) has a shaped ring which consists of a transparent or opaque, permanently elastic material and which has adhesive surfaces for joining the spectacle lens ( 10 ) to the shield ( 30 ).

The present invention relates to an adaptor for fixing spectacle lensesaccording to the preamble of Claim 1.

This invention relates to a frameless joining of commercial safetyglasses which have a continuous transparent shield or two separated,extremely curved transparent shields as an eye cover, in particular,sports glasses, sports sunglasses, diver's goggles and industrial safetyglasses, to spectacle lenses of individual lens strengths according tothe person wearing the safety glasses. People who must wear glasses havedifficulty wearing current safety glasses which typically havetransparent shield in the form of a continuous plate as an eye cover.These types of safety glasses, for example, are available under thetrade names Oakley M-Frame Series, Bolle Edge Series and BreakawaySeries, Alpina Gravity 0/Bel Air Series, Swiss Eye, etc.

Most producers offer exchangeable frame adapters that are inserted intothe spectacle frame for the fitting of spectacle lenses. These systems,however, have some serious disadvantages. For example, with sportsglasses, the largest distance between the safety glasses and the eyesincreases considerably, which, as a rule, is about 15 mm. This reducesshielding capacity of the shield or the two shields, so that wind swirlsmay occur between the shield and the eye. Furthermore, in unfavorableweather conditions, the shields tend to fog up. In order to clean theshields, it is necessary to remove the adapter. Furthermore,conventional frame adapters are rather heavy.

In diver's goggles, silicate spectacle lenses have for some time beenjoined to the rear areas of the shield of the diver's goggles by meansof hardened adhesives, such as an epoxy adhesive. This can result in achange of the chromatic dispersion. Moreover, there may be problems inwhich, when using the diver's goggles, the shield of the goggles has aconsiderably lower temperature, which is determined by the temperatureof the surrounding water, than the spectacle lenses, which are heated bythe warmth of the face of the goggles wearer. This difference intemperature causes the spectacle lenses to expand more than the shield.The spectacle lenses may loosen from the back due to this difference intemperature, but since the hardened adhesive is not elastic and unableto compensate for the stress caused by the varying expansiontemperature, the lenses may crack.

Classical safety glasses normally consist of frames and hardenedspectacle lenses provided with shielding sections. Hardened spectaclelenses, however, are very expensive and often must be replaced due toexcessive wear. Other safety glasses have an inserted frame adapter, asexplained above in connection with sports glasses. Safety glassesprovided with this type of frame adapter have the same disadvantages asthe sports glasses described above.

Another great problem, which reduces the suitability of the safetyglasses provided with frame adapters, is the astigmatism of obliquebundles which occurs with curved shields as a result of the angularadjusting position of the correcting spectacle lenses. This can beavoided only if it is possible to fix the correcting spectacle lenses sothat they are as vertical to the optical axis as possible, which isdifficult to impossible for curved shields.

These disadvantages considerably restrict the usability and theapplication of these safety glasses for the wearers.

The object of the present invention is to eliminate the above describeddisadvantages found in conventional plug-on adapter systems and to fixthe spectacle lens to the shields in a simpler, safer and morecompatible manner, i.e., with increased benefit to the spectacle.Further, an excessive increase in weight, which occurs with conventionalframe adapters, is to be avoided.

The solution is provided by an adapter with the features of claim 1.According to the invention, the adapter is a shaped ring of atransparent or opaque permanently elastic material, in which the shapedring has adhesive surfaces for joining the spectacle lens to the shield.The adapter according to the invention connects the rear of the shieldof a pair of safety glasses to the front of the spectacle lens tightlyand immovably, but reversibly, and thus also removably. The adapteraccording to the invention thus is able to finction completely withoutseats or frames for spectacle lenses. The system, which consists of apair of safety glasses and spectacle lens, is protected againstcondensation due to the hermetic seal of the space between the shieldand the spectacle lens. The weight of the adapter according to theinvention is only a fraction of that of a conventional frame adapter.Since the adapter is fastened reversibly and thus can be removed fromthe shield of the safety glasses and spectacle lens, said adapter isreusable.

Advantageous further developments result from the subordinate claims.The shaped ring may have a flat cross section or it may have the shapeof an adhesive strip, preferably with a thickness ranging between 0.5 mmto 2.0 mm. Adapters of this type are suitable, for example, for flatshields such as diver's goggles. The shaped ring may have a wedge-shapedcross section. One possible structure comprises a core of transparent oropaque material that is provided with adhesive surfaces in the form ofat least one layer with an adhesive material. These types of adapter aresuitable for lining strong curves at the front of positive lenses. Thedeciding factor for the use of adapters always are the anatomical oroptical requirements.

The core preferably is made of a plastic material, preferablypolycarbonate or nylon. This material can be stressed mechanically andcan withstand considerable temperature fluctuations without becomingporous.

In the following embodiments, the present invention is explained indetail by means of the attached drawings. Shown are:

FIG. 1, a perspective representation of the individual components of thesystem consisting of a shield of a pair of safety glasses, an embodimentof the adapter according to the invention and the spectacle lens;

FIG. 2a, the system of FIG. 1, in which the individual components areinterconnected;

FIG. 2b, an optical section through the system of FIG. 2;

FIGS. 3a through 3 c, lateral views of various embodiments of theadapter according to the invention;

FIG. 4a, a section through the curved flat shield of a pair of diver'sgoggles with a concave spectacle lens;

FIG. 4b, a section through the flat shield of a pair of diver's goggleswith a convex spectacle lens;

FIG. 5a, a perspective of a cross-section of the wedge-shaped adapter;

FIG. 5b, a cross-section through the adapter of FIG. 5a.

FIGS. 1 through 2b show a system 1 consisting of a spectacle lens 10, anadapter according to the invention 20 in the form of a shaped ring, anda shield 30 of a pair of safety goggles 40 or, for example, a pair ofsports glasses, diver's goggles or safety glasses. The spectacle lens 10is connected at the front to an adapter 20, whose lateral surfaces 21,22 consist of an adhesive material. The unit comprising the spectaclelens 10 and the adapter 20 is connected from the rear to the shield 30.The adhesive joint is fixed and immovable, but removable.

This is advantageous if the shield 30 is of a high optical andmechanical quality, and possibly has a rotation-symmetrical fundamentalcurve or base curve. Shields used in most commercial safety glasses meetthese requirements. Shields which only consist of a curved sheet are notsuitable. The spectacle lens 10 should preferably have the samecurvature or base curve as the shield 30. According to specific detailssuch as spacing of the eyes, corneal vertex distance, cutting height,lens thicknesses, in particular, with respect to very thick lenses andoblique astigmatism, the user should convert the thickness of thespectacle lenses in order to keep the astigmatism of oblique bundleswhich can be expected with curved shields 30 and when the spectaclelenses 10 are no longer in vertical position, within non-interferinglimits. This conversion is part of the expert knowledge of opticiansand, therefore, does not require detailed explanation (compare Pforte,Der Feinoptiker [The High-Precision Optician], Part II).

Practically all types of single or multifocal spectacle lenses can beprocessed if the respective fundamental optical requirements are takeninto consideration.

FIGS. 3a-3 c show various embodiments of an adapter 20, 20′, 20″. Theadapters 20, 20′ shown in FIG. 3a and 3 b are self-adhesive strips of0.5 mm or 2 mm thickness of a permanently elastic transparent or opaquematerial. Also suitable are adhesive strips produced by the company 3Mwith the designation VHB 4905 P, 4910 F, 4912 F, 4915 F, 4918 F. Theadapter 20″ shown in FIG. 3c has a core 23 made of a plastic materialsuch as nylon or polycarbonate, which is approximately 3.5 mm thick andlined on both sides with a self-adhesive layer 24, which is about 0.5 mmthick.

FIGS. 4a and 4 b show sections through a concave or convex spectaclelens 10 a, 10bb, which is fixed on a curved shield 30 a of a pair ofsports glasses 40 a, or a flat shield 30 b of a pair of diver's goggles40 b. FIG. 4a shows that the curved shield 30 a and the front of thespectacle lens 10 a have the same curvature or basic curve, so that aflat adapter 20, 20′ can be used. By contrast, the front of the convexspectacle lens 10 b in FIG. 4b has a strong curvature, whereas theshield 30 b of the pair of diver's goggles 40 b is flat. This isbalanced by using a stronger adapter 20″.

FIGS. 5a and 5 b show another adapter 25, which has a wedge-shaped crosssection. The wedge-shaped cross section also allows the balancing of thedifferent curvatures of the shield 30 and the front of the spectaclelens 10.

What is claimed is:
 1. Adapter (20) for reversibly fixing a spectacle lens (10) to a shield (30) of a pair of safety glasses (40), said adapter (20) comprising a shaped ring with a flat cross section, said shaped ring comprising permanently elastic material, in which said shaped ring has adhesive surfaces for joining a spectacle lens (10) to a shield (30).
 2. Adapter as defined in claim 1, characterized by the fact that the shaped ring comprises an adhesive tape.
 3. Adapter as defined in claim 2 wherein said adhesive tape has a thickness between 0.5 mm and 2.0 mm.
 4. Adapter (20) for reversibly fixing a spectacle lens (10) to a shield (30) of a pair of safety glasses (40), said adapter (20) comprising a shaped ring with a wedge-shaped cross section, said shaped ring comprising a permanently elastic material, in which said shaped ring has adhesive surfaces for joining a spectacle lens (10) to a shield (30).
 5. Adapter (20) for reversibly fixing a spectacle lens (10) to a shield (30) of a pair of safety glasses (40), said adapter (20) comprising a shaped ring with a flat cross-section, said shaped ring comprising a permanently elastic material, in which said shaped ring has adhesive surfaces for joining a spectacle lens (10) to a shield (30), characterized by the fact that the shaped ring has a core (23) of a transparent material which has adhesive surfaces in the form of at least one layer (24) of an adhesive material.
 6. Adapter as defined in claim 5, characterized by the fact that the core consists of a plastic material.
 7. Adapter as defined in claim 6 wherein said plastic material is selected from the group consisting of polycarbonate and nylon.
 8. System (1) comprising a pair of safety glasses (40) with at least one shield (30) and spectacle lenses (10) reversibly fixed thereon, characterized by the fact that the spectacle lenses (10) are attached to the shield by means of an adapter (20) according to any one of claims 1, 2-7 or 10-14.
 9. System as defined in claim 1, in which the safety glasses are selected from the group consisting of sports glasses, sport sunglasses, diver's goggles, and industrial safety glasses.
 10. Adapter (20) for reversibly fixing a spectacle lens (10) to a shield (30) of a pair of safety glasses (40), said adapter (20) comprising a shaped ring with a flat cross section, said shaped ring comprising a permanently elastic material, in which said shaped ring has adhesive surfaces for joining a spectacle lens (10) to a shield (30), wherein said permanently elastic material is transparent.
 11. Adapter (20) for reversibly fixing a spectacle lens (10) to a shield (30) of a pair of safety glasses (40), said adapter (20) comprising a shaped ring with a flat cross section, said shaped ring comprising a permanently elastic material, in which said shaped ring has adhesive surfaces for joining a spectacle lens (10) to a shield (30), wherein said permanently elastic material is opaque.
 12. Adapter (20) for reversibly fixing a spectacle lens (10) to a shield (30) of a pair of safety glasses (40), said adapter (20) comprising a shaped ring with a flat cross section, said shaped ring comprising a permanently elastic material, in which said shaped ring has adhesive surfaces for joining a spectacle lens (10) to a shield (30), characterized by the fact that the shaped ring has a core (23) of an opaque material which has adhesive surfaces in the form of at least one layer (24) of an adhesive material.
 13. Adapter as defined in claim 12, characterized by the fact that the core consists of a plastic material.
 14. Adapter as defined in claim 13 wherein said plastic material is selected from the group consisting of polycarbonate and nylon.
 15. System (1) comprising a pair of safety glasses (40) with at least one shield (30) and spectacle lenses (10) reversibly fixed thereon, characterized by the fact that the spectacle lenses (10) are attached to the shield by means of an adapter (20) according to any one of claims 1, 2-7 or 10-14 and wherein said at least one shield is transparent and wherein said spectacle lenses are circular. 